US839637A - Pocket-ammeter. - Google Patents

Description

No. 839,637. PATENTED DEC. 25, 1906. H. POEHN & M. JURUIGK.

POCKET AMMETBR.

APPLICATION FILED 1130.1, 1905.

m mvm W 2 Law fi w WITNESSES: ci a UNITED srArEs PATENT. OFFICE.

HERMANN POEHN, OFJERSEY CITY, NEW JERSEY, AND MAXIMILI'AN JURUICK, OF NEW YORK, N. Y.

POCKET-AMMETER.

Specification of Letters Patent.

Patented Dec. 25, 1906.

Application filed December 1, 1906. Seria1No. 289,749.

To all whom it may concern -Be it known that we, HERMANN Forum, a resident of J erse City, in the county of Hudson.and State 0 New Jersey, and MAXIMIL- IAN JURUICK, a resident of New York, in the county andState of New York, citizens of. the United States, have ointly invented certain new and useful Improvements in Pocket- Ammeters, of which the following is a specification.

This invention has reference to improvements in pocket-ammeters, and pertains particularly to -that kind of ampere-meters known as the watchcase type.

The novel ammeter is a direct-readin instrument. Its scale usually ranges rom zero to thirty or forty or fifty amperes or any other suitable number. i

It is thespecial object of this invention to provide a pocket-ammeter with a peculiarlyshaped armature located between the poles of an electromagnet of nearly-circular form. The weight or the mass of the material of the armature is so arranged that the inner portion of same is heaviest, while the ends are narrow and light.

The novel ammeter, further, is provided with a loose rin for the adjustment of the starting-point o the armature or its normal position in relation to the poles of the electromagnet. This is not done, directly, but by means of the hair-spring generally employed in such instruments and by a pinion and gearwheel, as will be fully explained farther down.

The invention is illustrated in the accompanying drawings, in which- Figure 1 represents in top plan view a pocket-ammeter which embodies our invention. Fig. 2 illustrates same in top plan view with dial and pointer removed. Fig. 3 is a rear view of the instrument with the rear cover removed. Fig. 4 is a detail view of the essential operative mechanism, and Fig. 5 is a plan view of Fig. 4.

Similar characters of reference denote like parts in all the figures.

In the drawings, a represents the casing, which is cut out in the rear, as shown in Fig. 3. At the bottom an opening I) is cut into the casing to allow of passing through one end of the contact 0. Just opposite this openin there is the knob d, which is hollowed out an provided with a screw-thread on the inside 'h. (See Fig. 2.)

for the purpose of receiving one end of the second contact 0.

Within the casing there is mounted a brass disk e, which has a central opening and. a tongue .2. The ton ue extends inwardly to the center of the dis of nearly-circular shape is secured on the dis by means of screws. The core f 2 of the magnet consists of soft iron, which retains practicall noresidu'al magnetism when no current ows through same. The poles f of the ma net are turned inwardly, as shown in Fig. 4. he magnet has two windings of wire. The two ends ww, one of each winding, are soldered to the metal diske, while the two other ends w w are soldered to a small piece of metal g, which is provided with a threaded opening for receivin the one end of the contact 0 that has a threa on the outside. A ring of insulating material 0 is secured to the contact 0. Within the casing there is a curved piece of insulating material 0 which has 'a circular opening for the passage of the contact 0. The ring 0 and the piece a insulate the contacts from the casing, which forms part of the circuit of the magnet-wire. The current passes from the contact 0 through the electroma net, the casing, the knob d, and out throug the contact 0.

Upon the disk e there is mounted a bridge The bridge is secured 1n the center of the disk and extends u wardly into'a branch h. It carries two sma 1 shafts i j, which rest in the disk e, each on a hardened plate to insure of easy movement; but

this is not shown on the drawin s. The shaft,

i rests on the tongue e of the dis e and passes through the brid e h and dial is. A pointer is is attached to the top end of this shaft. A small pinion Z is mounted on the shaft '5 right below the bridge and a hair-spring 8 below the pinion. The shaft 7' carries a'gear-wheel m and below same the armature 'n, which is in one horizontal plane with the poles of the electromagnet. The bottom surface of the An electromagnet g disk carries a-loose ring 0, which is surrounded by a supporting-ring 0. The ring 0 has a rectangular arm 0 extending upward. The outer end of the hair-spring is secured to this arm, while the inner end of same is fastened to a small hub on the shaft 'i.

The armature n also is made of soft iron, which quickly demagnetizes.

10 5 It is of pecul- 7 pointed at the two ends and increases 111 widthtoward the center cross-bar n, which is broadest. In this Way theweight of the armature is so distributed that the pointed ends, which are normally near the oles of the electromagnet, are very light, w 'Ie the center cross-bar is relativelyheavy. When current flows through the electr'omagnet, then the distance between the heavy bar of the armature and the poles of the electro- -'mag'net decreases, becausethe armature is turned in accordance with the strength of the -'em'rent flowing through the instrument.

Asabeve stated, the wire spring s has-one endattached to'the rectangular arm 0 of the loosering 0, while the inner-end is secured to the smal hub on the pinion andspring shaft 11-. By turningthe loose ring the starting- -pointor the osition of the armature ends in relation to "t e poles of the electromagnet may be adjusted. This is another feature of this invention. It is plainly understood that the ointer k", which is secured to the top end of 't e pinion ands ring shaft, will move when the spring is a ected by the armature, which moves the gear and pinion when current flows throughthe instrument.

Having thus described our invention, we claim as new and desireto secure by Letters Patent 1. A ocket-ammeter comprising a casing, a meta disk mounted therein, an electromagnet secured to said disk, an S-shaped armature mounted on a movable shaft between the poles of the electromagnet, a gear-wheel -on said shaftabove the armature, a pinion second shaft in the center-ofthe instrument,

a ointer on the top end of the pinion-shaft, a 'al below the polnter, a hair-spring on the pinion-shaft below the pinion, and a loose ring on the bottom surface ofthe-disk having ,a rectangular arm to which one end of the hair-spring is secured whereby the position of the armature ends may be adjusted in'relation to the poles of the electromagnet.

'3. In a pocket-ammeter an electromagnet of nearly-circular form and haying turned-in poles, an 'S-shaped armature'mounted 'between said poles and in one plane with same on a movable shaft, a gear-wheel on said shaft above the armature, a pinion mounted on a second shaft, a hair-spring on thepinionshaft below said pinion, and a loose ring having a rectan lar arm to which one end ofthe hair-spring 1s secured whereby the position of the armature ends may be adjusted in relation to the poles of the electromagne't.

In testimony whereof we have hereunto set our hands, this 29th day of November, 1905, in the presence of two subscribing witnesses.

' HERMANN 'POEHN. MAX. JURUICK,

Witnesses:

LUDWIG K- Berna, JAMES J. ASTARITA.

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